1. Field of the Invention
The invention relates to novel pyrrolylketo and pyrrolylamino acids, esters and amides of the formulae (I) and (II) as defined herein and pharmaceutically acceptable salts thereof, pharmaceutical compositions thereof and their use in treating diseases and conditions of mammalian subjects, including humans, which are characterized by reduced blood flow, reduced oxygen availability or reduced carbohydrate metabolism in the cardiovascular system of the subject; such conditions include ischaemic heart disease (particularly angina pectoris and myocardial infarction) and cardiac failure.
2. Description of the Prior Art
2-Pyrroleglyoxylic acid and 2-pyrrolylglycine [alpha-amino-(2-pyrrolyl)acetic acid]and certain esters and amides thereof are known compounds. The former are disclosed by Oddo, Gazz. chim ital., 50, 258 (1920); Chem. Abstr., 15, 2096 (1921) and in U.S. 3,202,654. The latter reference also discloses alpha-amino-(2-pyrrolyl)acetic acid and the use of these compounds as intermediates for preparing penicillins. 2-Pyrroleglyoxylic acid ethyl ester is disclosed in South African Pat. No. 69 01,243; Chem. Abstr., 72, 97445W (1970) as a flavor enhancing agent for tobacco.
U.S. Pat. Nos. 3,920,730; 3,994,954 and 4,108,854 disclose N-acyl-alpha-heteroaromatic glycines, including N-acyl-2-pyrrolylglycines unsubstituted in the pyrrole moiety, in which the N-acyl group is an amino protecting group. These compounds are disclosed as being useful intermediates for the preparation of penicillins, and cephalosporins.
No pharmaceutical use for either 2-pyrroleglyoxylic acid, the corresponding alpha-amino acid or their derivatives are known.
In U.S. Pat. No. 4,148,920 L- and DL-phenylglycines of the formula ##STR2## where R.sub.1 is hydrogen or methyl and R.sub.2 is NH.sub.2, OH or completes a carboxylic ester group are disclosed as useful in treating diseases and conditions characterized by reduced blood flow, oxygen availability or reduced carbohydrate metabolism in the cardiovascular system. The D-isomers are disclosed as inactive.